Abrupt Northwest Atlantic deep-sea oxygenation decline preceded the Palaeocene-Eocene Thermal Maximum
Abrupt Northwest Atlantic deep-sea oxygenation decline preceded the Palaeocene-Eocene Thermal Maximum
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DOI：
10.1016/j.epsl.2023.118304
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发表时间：
2023-09
影响因子：
5.3
通讯作者：
P. Xue;Liao Chang;Ellen Thomas
中科院分区：
文献类型：
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作者：
P. Xue;Liao Chang;Ellen Thomas
古新世-始新世热峰期（PETM，55.93 Ma）海洋氧化还原条件的重建提供了潜在的PETM触发和生物周转的关键信息。广泛的海洋脱氧已被证明发生在PETM期间，但确切的时间和区域变化知之甚少。在这里，我们记录保存完好的磁化石的磁性和晶体形态的变化在国际海洋发现计划（IODP）网站U1409（2913米palaeodepth）和U1403（4374米palaeodepth）在整个PETM，并使用这些代理跟踪西北大西洋palaeoredox变化。我们的记录表明，这些地点的深海氧合逐渐减少，在PETM之前的几十万年开始，在PETM之前达到最低值250千公里，然后是广泛的增加。古氧化还原条件的这种模式可能反映了深海环流和海洋温度的变化。因此，我们提供了证据的存在PETM变暖的前兆，并建议，海洋环流的变化可能发挥了重要作用，在触发碳释放到海洋-大气系统在PETM发作。
Reconstruction of oceanic redox conditions across the Palaeocene-Eocene Thermal Maximum (PETM, ∼55.93 Ma) provides crucial information on potential PETM triggers and biotic turnover. Widespread oceanic deoxygenation has been documented to occur during the PETM, but the exact timing and regional variability is poorly understood. Here we document well-preserved magnetofossils with large variations in magnetic properties and crystal morphologies at International Ocean Discovery Program (IODP) Sites U1409 (∼2913 m palaeodepth) and U1403 (∼4374 m palaeodepth) across the PETM, and use these proxies to trace Northwest Atlantic palaeoredox changes. Our records suggest that deep-sea oxygenation at these sites decreased gradually, starting several hundred thousand years before the PETM, reaching a minimum ∼50 ky before the PETM, followed by a broad increase. This pattern in palaeoredox conditions likely reflects changes in deep-sea circulation and ocean temperature. We thus provide evidence for the existence of precursors to PETM warming, and suggest that ocean circulation changes might have played an important role in triggering carbon release to the ocean-atmosphere system at the PETM onset.